//
//  UsbCameraView.swift
//  usb_camera_android
//
//  iOS 原生预览 PlatformView：用 AVCaptureVideoPreviewLayer 直接渲染 session。
//

import AVFoundation
import Flutter
import UIKit

/// 以 AVCaptureVideoPreviewLayer 作为 backing layer 的 UIView。
final class UsbCameraPreviewUIView: UIView {
    override class var layerClass: AnyClass { AVCaptureVideoPreviewLayer.self }
    var previewLayer: AVCaptureVideoPreviewLayer {
        return layer as! AVCaptureVideoPreviewLayer
    }
}

final class UsbCameraView: NSObject, FlutterPlatformView {
    private let previewView: UsbCameraPreviewUIView

    init(engine: UsbCameraEngine, frame: CGRect) {
        self.previewView = UsbCameraPreviewUIView(frame: frame)
        super.init()
        previewView.previewLayer.session = engine.captureSession
        previewView.previewLayer.videoGravity = .resizeAspect
    }

    func view() -> UIView {
        return previewView
    }
}

final class UsbCameraViewFactory: NSObject, FlutterPlatformViewFactory {
    private let engine: UsbCameraEngine

    init(engine: UsbCameraEngine) {
        self.engine = engine
        super.init()
    }

    func createArgsCodec() -> FlutterMessageCodec & NSObjectProtocol {
        return FlutterStandardMessageCodec.sharedInstance()
    }

    func create(withFrame frame: CGRect, viewIdentifier viewId: Int64,
                arguments args: Any?) -> FlutterPlatformView {
        return UsbCameraView(engine: engine, frame: frame)
    }
}